1. Field of the Invention
This invention is directed to a power zoom device which changes a focal length of the lens by a motor. More precisely, it is concerned with a speed control of the zoom device.
2. Description of Related Art
Conventional cameras use a power zoom mechanism which changes a focal length by driving a zoom lens with a motor.
In general, power zooms are operates by using a switch which enables an operation in either direction from a neutral position. Other devices use more than one selector position on both sides of the neutral position in order to change the zooming speed by the switch position.
In the conventional power zooming devices, because there are a small number of selector positions, only two speeds or so can be selected, and a speed corresponds to a selector position, depending on the switch's absolute position.
However, when increasing the selector positions of the zooming to enhance the maneuverability of the zoom, with the selector positions and zooming speeds corresponding one by one as described above, the zoom lens cannot stop immediately if the selector is located far from the neutral position, because it takes time to return to the neutral position.